Lance Armstrong is hurt following a collision on the Tour of California. Photograph: Ken Conley/EPA

The global media expressed varying degrees of confidence in Lance Armstrong following Floyd Landis's allegations against the seven-times Tour de France winner but shared in their response a world-weariness over the ongoing battle for cycling's credibility.

Armstrong has fiercely denied Landis's claims that he used performance-enhancing drugs, and the collective reaction has been to ask where the evidence is for Landis's allegations and whether anything can ever be proven.

There is agreement that the development of new testing techniques, allied to the involvement of various global organisations such as the World Anti-Doping Agency and United States Anti-Doping Agency, could be crucial. But Landis's history of denial of his own drug use until now has led some to argue that his word must be treated with caution in the absence of substantiated evidence.

Bill Strickland, editor at large for the US-based Bicycling magazine, told ABC News: "Things haven't been going well for [Landis]. His racing career is suffering. He's admitted in public that his legal troubles [in trying to clear his name] have more or less ruined him financially. This is not going to sway anyone's opinion. I really believe that people have their opinions of Lance, and they look for evidence to support that."

Commenting for Bicycling Magazine's website, Joe Lindsey says: "Armstrong has a long history of battling accusations of doping. There have been many. But in every one of these instances, Armstrong has successfully batted away the allegations. And he may do so again. Part of the issue is the timing. The totality of all the circumstantial evidence is troubling. But, spread out over a decade, it lacks weight. Perhaps more important, Landis stubbornly proclaimed his innocence until these emails. The logic goes that he was lying then so we can't trust him now."

"But," says Lindsey, "there are glimmers that United States Anti-Doping Agency (Usada) may not be the only agency looking at Landis's claims. Both the NY Times and the Times of London are reporting that Jeff Novitzky is involved in the investigation. It's not clear how Novitzky, an agent at the Office of Criminal Investigations division of the Food and Drug Administration, might be involved, but he's best known for prosecuting Barry Bonds and others in the Balco drug scandal. Novitzky's purported involvement raises the stakes considerably."

George Vecsey writes in the New York Times that Armstrong will find it tough to escape the suspicion after his latest accuser went public. "This is one of those rare times that a prominent cyclist has openly incriminated an entire team and by consequence the culture of professional cycling. [Landis's] accusations sound as if he were there," writes Vecsey.

"He's loopy, but I don't think he has the imagination to make up all this stuff. He has now personally indicted an entire team of familiar names ... The Usada will investigate, and federal investigators will make sure those questioned are telling the truth. But I have no faith in organised cycling to take this on in any serious way. No matter where it goes from here, I don't think Lance Armstrong can break away from this one."

For CBS news in America, John Bentley commented: "The question now is: can Landis prove anything he said? Yes, according to a doping expert. The World Anti-Doping Agency said they would open an investigation into Landis's allegations, and new doping detection methods will be a part of that. 'We're getting better technology to detect prohibited substances that are abused,' said Dr Gary Wadler of Wada. 'We'll be able to look backwards as far back as eight years to see if at the time of a given event when the specimen was collected if there were doping agents in the urine. Only Lance Armstrong knows if he has something to hide or not,' he said – but he had two words of advice for those who think they may have gotten away with doping in the past. 'Athlete beware.'"

Owen Slot in the Times hinted that Armstrong would endure. "Do yesterday's allegations by Floyd Landis spell the end for Lance Armstrong?" he asks. "Probably not. Armstrong has had more claims of doping against him than he has won Tours de France. This is just the latest, it is possibly the most public, arguably the most sensational and the fact that it comes from a former team-mate brings with it obvious tones of inside information.

"However, previous cases linking Armstrong with the use of illegal drugs have contained more detail, yet been killed off in the technicalities of legal debate. Yet they remain mere allegations, all of which Armstrong denies. Landis admits that he has no proof bar his own testimony.

"The International Cycling Union declared yesterday that it has no interest in pursuing the case, which is interesting given that the sport's world governing body was implicated in Landis's allegations. Instead, the case has been passed on to the US Anti-Doping Agency, which has brought in Jeff Novitzky, the federal agent who was instrumental in busting the Balco doping ring. If Landis's claims are anything more than the vengeful ragings of a cheat, Novitzky may enjoy pursuing them."